Island



(No Model.)

' M. L: BOSWORTH.

DENTAL MALLET. No. 465,337. Patented Dec. 15,1891,

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UNITED STATES MARTIN L. BOSXVORTH, OF IVARREN,

PATENT OFFICE.

RHODE ISLAND, ASSIGNOR OF ONE FIFTH TO JOHN VATERMAN, BENJAMIN B. MARTIN, AND BENJAMIN M.

BOS'WORTH, ALL OF SAME PLACE.

DENTAL MALLET.

SPECIFICATION forming part of Letters Patent No. 465,337, dated December 15, 1891.

Application filed August 30,1889.

To all whom it may concern.

Be it known that I, MARTIN L. 'BOSWORTH, of the town of lVarren, in the county of Bristol, in the State of Rhode Island, have invented a new and useful Improvement in Dental Pluggers; and I declare the following to be a specification thereof, reference being had to the accompanying drawings.

Figures 1 and 3 are views, partly in side elero vation and partly in section, of myimproved dental plugger. Fig. 2 isa top plan of the exterior of my invention. Fig. 4 is aside elevation of the same.

Like letters indicate like parts.

My invention relates to that class of dental instruments commonly called pluggers, which are used in the filling of teeth to com- 1 pact the gold in the cavity of the tooth.

It consists of a spring-actuated hammer 2o movable in an are within as head whichhas a suitable passage-way therefor, a plugger which also moves in a suitable passage-way;

a bent lever pivotally mounted, one of whose arms is adapted to move the plugger back and forth and the other of whose arms carries a spring and pawl to engage said hammer by means of a notch in the latter and means to disengage said pawl, substantially as herein- 7 after specified.

0 In the drawings I show a handle having two metallic extensions, Figs. 2 and 3, and a semicircular head or case with an extension, which is pivotally connected to the handle-extensions by a set-screw K, whereby a hinge 3 5 connection is made between the handle and tool-head, as seen-in Figs. 2 and 3, thus allowing an adjustment of the tool to bring the plugging-point into any desired angle with the handle in order to more easily reach any 0 cavity in the teeth, whatever its location may be. The screw K is tightened when the head is so adjusted. This case has two plane sides and a curved rim A, bent in the arc of a circle, anda straight base-plate Z, as fully illustrated 5 in Figs. 1 and 3. Parallel with the inner surface of the rim A are ribs or guides G J, at

tached to one of the side plates.

Serial No. 322,449. (No model.)

shape and having a notch on its inner side, as

seen in Figs. 1 and'3.

O is a spring fastened by screws to the run of the case, as in Fig. 3, or to the base-plate,

as in Fig. 1, and bent so that its free end bears against the end of the hammer B. The tension of this spring may be regulated by the screw N, as shown. The hammer Bis movable in the passage-way between the rim A and the guides G J.

D is the plugger, which has a socket at its outer end to receive a plugging-point, and

it is movable in the passage-way, which is formed gby the rim A and the fixed guide a, and which passage-way is a continuation of the curved passage formed by the rim A and guides G J aforesaid. A bent lever having two arms E and H is pivotedat x. The-arm H is pivoted to the pluggerD at its outer end, and E is the other arm of the bent lever and is provided with a pawl F, The pawl has two beveled projections and a socket. The arm E enters said socket. A spiral spring I surrounds the arm E and has its bearingsat one end against the'arm H and at the other end against the bottom of the pawl F. One of the beveled projections of the pawl enters the 7 5 notch of the hammer B, and the other is intended to strike against and move over a beveled end of the rib or guide G. A spring L may be secured to the under side of the arm H, with its free end resting on the base-plate Z, as in Fig. 1, or to the base-plate Z, with its free end bearingagainst a toe M of the arm H, as in Fig. 3.

The ends of the hammer B and plugger D, which are opposite each other, have bosses which come in contact with each other when the blow is struck. a

The operation of the instrument is as follows: The tool is seized by the handle and the end of the plugger-point is placed in the desired position in the cavity of the tooth to press in the metallic filling, as usual. Oon

tinned pressure forces the plugger and point inwardly. This movement of the plugger turns the bent leverE II. V

The arm E by the pawl F, which engages with the notch of the ham1nerB by the force of the spring I, moves back the hammer B and compresses the spring 0. When the lateral projection of the pawl F strikes against and presses over the beveled end of the rib'G, the pawl F is thereby forced down on the arm E against the pressure of the spring I, and is thus disengaged from the notch of the hammer L. The hammer, being no longer held by said pawl,is free to yield to the pressure of the spring (J and is driven with much force by the spring 0 against the plugger D. The blow thus delivered is received upon the metal in the tooth. Now when the pressure of the instrument upon the filling ceases, the spring L normally carries the bent lever E Ilto its firstposition,

'andthe pawl F, as soon as it comes to the notch in the hammer, is engaged therewith by the spring I.

In my invention the plugger is extensible, at .an angle with the handle, and the plugger. receives a direct and automatic blow from a spring-actuated hammer, instead-ofacommu- .nicated rblow, as in the dental pluggers commonly in use.

In my device the external power used to operate the implement is not derived from a dental engine, as is commonly the case in usingsuch instruments, but simply fro m continuedpressure upon the outer end of the plugging-point.

I claim as anovel and useful invention and desire to secure by Letters Patent 1. In a dental instrument having a handle, the combination of a movable plugger mounted therein at an angle with said handle, a bent hammer movable lengthwise in a passage of corresponding shape, a spring having a bearing against the inner end of said ham- .mer, a connecting-piece between said hammer and plugger, adapted tocornpel their travel together inwardly when the outer end of the 7 ver E H, the axis 00, on which said bent lever E H is mounted, the pawl F, the springl, the fixed guides GJ, and the spring L, all :ar-'

the purpose specified.

MARTIN L. BOSWOR'IH. \Vitnesses:

JAMES C. OoLLINs, CHARLES H. PAGE.

ranged and operating substantially as and (for 

